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author | Kent Overstreet <koverstreet@google.com> | 2013-03-23 16:11:31 -0700 |
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committer | Kent Overstreet <koverstreet@google.com> | 2013-03-23 16:11:31 -0700 |
commit | cafe563591446cf80bfbc2fe3bc72a2e36cf1060 (patch) | |
tree | c8ae27b13dcdb0219634376ca5e667df32b1173a /drivers/md/bcache/movinggc.c | |
parent | ea6749c705d9e629ed03c7336cc929fc6014b834 (diff) | |
download | linux-cafe563591446cf80bfbc2fe3bc72a2e36cf1060.tar.gz linux-cafe563591446cf80bfbc2fe3bc72a2e36cf1060.tar.xz |
bcache: A block layer cache
Does writethrough and writeback caching, handles unclean shutdown, and
has a bunch of other nifty features motivated by real world usage.
See the wiki at http://bcache.evilpiepirate.org for more.
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Diffstat (limited to 'drivers/md/bcache/movinggc.c')
-rw-r--r-- | drivers/md/bcache/movinggc.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/md/bcache/movinggc.c b/drivers/md/bcache/movinggc.c new file mode 100644 index 000000000000..c69fc92b02cf --- /dev/null +++ b/drivers/md/bcache/movinggc.c @@ -0,0 +1,254 @@ +/* + * Moving/copying garbage collector + * + * Copyright 2012 Google, Inc. + */ + +#include "bcache.h" +#include "btree.h" +#include "debug.h" +#include "request.h" + +struct moving_io { + struct keybuf_key *w; + struct search s; + struct bbio bio; +}; + +static bool moving_pred(struct keybuf *buf, struct bkey *k) +{ + struct cache_set *c = container_of(buf, struct cache_set, + moving_gc_keys); + unsigned i; + + for (i = 0; i < KEY_PTRS(k); i++) { + struct cache *ca = PTR_CACHE(c, k, i); + struct bucket *g = PTR_BUCKET(c, k, i); + + if (GC_SECTORS_USED(g) < ca->gc_move_threshold) + return true; + } + + return false; +} + +/* Moving GC - IO loop */ + +static void moving_io_destructor(struct closure *cl) +{ + struct moving_io *io = container_of(cl, struct moving_io, s.cl); + kfree(io); +} + +static void write_moving_finish(struct closure *cl) +{ + struct moving_io *io = container_of(cl, struct moving_io, s.cl); + struct bio *bio = &io->bio.bio; + struct bio_vec *bv = bio_iovec_idx(bio, bio->bi_vcnt); + + while (bv-- != bio->bi_io_vec) + __free_page(bv->bv_page); + + pr_debug("%s %s", io->s.op.insert_collision + ? "collision moving" : "moved", + pkey(&io->w->key)); + + bch_keybuf_del(&io->s.op.c->moving_gc_keys, io->w); + + atomic_dec_bug(&io->s.op.c->in_flight); + closure_wake_up(&io->s.op.c->moving_gc_wait); + + closure_return_with_destructor(cl, moving_io_destructor); +} + +static void read_moving_endio(struct bio *bio, int error) +{ + struct moving_io *io = container_of(bio->bi_private, + struct moving_io, s.cl); + + if (error) + io->s.error = error; + + bch_bbio_endio(io->s.op.c, bio, error, "reading data to move"); +} + +static void moving_init(struct moving_io *io) +{ + struct bio *bio = &io->bio.bio; + + bio_init(bio); + bio_get(bio); + bio_set_prio(bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); + + bio->bi_size = KEY_SIZE(&io->w->key) << 9; + bio->bi_max_vecs = DIV_ROUND_UP(KEY_SIZE(&io->w->key), + PAGE_SECTORS); + bio->bi_private = &io->s.cl; + bio->bi_io_vec = bio->bi_inline_vecs; + bio_map(bio, NULL); +} + +static void write_moving(struct closure *cl) +{ + struct search *s = container_of(cl, struct search, cl); + struct moving_io *io = container_of(s, struct moving_io, s); + + if (!s->error) { + trace_bcache_write_moving(&io->bio.bio); + + moving_init(io); + + io->bio.bio.bi_sector = KEY_START(&io->w->key); + s->op.lock = -1; + s->op.write_prio = 1; + s->op.cache_bio = &io->bio.bio; + + s->writeback = KEY_DIRTY(&io->w->key); + s->op.csum = KEY_CSUM(&io->w->key); + + s->op.type = BTREE_REPLACE; + bkey_copy(&s->op.replace, &io->w->key); + + closure_init(&s->op.cl, cl); + bch_insert_data(&s->op.cl); + } + + continue_at(cl, write_moving_finish, NULL); +} + +static void read_moving_submit(struct closure *cl) +{ + struct search *s = container_of(cl, struct search, cl); + struct moving_io *io = container_of(s, struct moving_io, s); + struct bio *bio = &io->bio.bio; + + trace_bcache_read_moving(bio); + bch_submit_bbio(bio, s->op.c, &io->w->key, 0); + + continue_at(cl, write_moving, bch_gc_wq); +} + +static void read_moving(struct closure *cl) +{ + struct cache_set *c = container_of(cl, struct cache_set, moving_gc); + struct keybuf_key *w; + struct moving_io *io; + struct bio *bio; + + /* XXX: if we error, background writeback could stall indefinitely */ + + while (!test_bit(CACHE_SET_STOPPING, &c->flags)) { + w = bch_keybuf_next_rescan(c, &c->moving_gc_keys, &MAX_KEY); + if (!w) + break; + + io = kzalloc(sizeof(struct moving_io) + sizeof(struct bio_vec) + * DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS), + GFP_KERNEL); + if (!io) + goto err; + + w->private = io; + io->w = w; + io->s.op.inode = KEY_INODE(&w->key); + io->s.op.c = c; + + moving_init(io); + bio = &io->bio.bio; + + bio->bi_rw = READ; + bio->bi_end_io = read_moving_endio; + + if (bio_alloc_pages(bio, GFP_KERNEL)) + goto err; + + pr_debug("%s", pkey(&w->key)); + + closure_call(&io->s.cl, read_moving_submit, NULL, &c->gc.cl); + + if (atomic_inc_return(&c->in_flight) >= 64) { + closure_wait_event(&c->moving_gc_wait, cl, + atomic_read(&c->in_flight) < 64); + continue_at(cl, read_moving, bch_gc_wq); + } + } + + if (0) { +err: if (!IS_ERR_OR_NULL(w->private)) + kfree(w->private); + + bch_keybuf_del(&c->moving_gc_keys, w); + } + + closure_return(cl); +} + +void bch_moving_gc(struct closure *cl) +{ + struct cache_set *c = container_of(cl, struct cache_set, gc.cl); + struct cache *ca; + struct bucket *b; + unsigned i; + + bool bucket_cmp(struct bucket *l, struct bucket *r) + { + return GC_SECTORS_USED(l) < GC_SECTORS_USED(r); + } + + unsigned top(struct cache *ca) + { + return GC_SECTORS_USED(heap_peek(&ca->heap)); + } + + if (!c->copy_gc_enabled) + closure_return(cl); + + mutex_lock(&c->bucket_lock); + + for_each_cache(ca, c, i) { + unsigned sectors_to_move = 0; + unsigned reserve_sectors = ca->sb.bucket_size * + min(fifo_used(&ca->free), ca->free.size / 2); + + ca->heap.used = 0; + + for_each_bucket(b, ca) { + if (!GC_SECTORS_USED(b)) + continue; + + if (!heap_full(&ca->heap)) { + sectors_to_move += GC_SECTORS_USED(b); + heap_add(&ca->heap, b, bucket_cmp); + } else if (bucket_cmp(b, heap_peek(&ca->heap))) { + sectors_to_move -= top(ca); + sectors_to_move += GC_SECTORS_USED(b); + + ca->heap.data[0] = b; + heap_sift(&ca->heap, 0, bucket_cmp); + } + } + + while (sectors_to_move > reserve_sectors) { + heap_pop(&ca->heap, b, bucket_cmp); + sectors_to_move -= GC_SECTORS_USED(b); + } + + ca->gc_move_threshold = top(ca); + + pr_debug("threshold %u", ca->gc_move_threshold); + } + + mutex_unlock(&c->bucket_lock); + + c->moving_gc_keys.last_scanned = ZERO_KEY; + + closure_init(&c->moving_gc, cl); + read_moving(&c->moving_gc); + + closure_return(cl); +} + +void bch_moving_init_cache_set(struct cache_set *c) +{ + bch_keybuf_init(&c->moving_gc_keys, moving_pred); +} |